Overall improvementsBing Search. The jury's still out, for me, on whether this is a help or a hindrance. When you use the Search charm, by default Win8.1 not only searches your documents (as you would expect) and programs and settings (which you may or may not expect), but it also searches the Web. Certain search terms trigger "hero" displays of images, video, and audio, ready for you to buy. I'm sure the new search does wonders for Bing's hit counts, and it certainly gives Microsoft more information about what interests you -- all the better to make a sale -- but only you can decide if it helps give you more information at a slower pace or if it plasters the results page with useless garbage. Don't like to see all that stuff? Click on the Everywhere line and choose Settings, Files, Web images, or Web videos. To turn Bing Search off permanently, in Metro PC Settings, choose Search & Apps/Search, then turn off Bing.

Internet Explorer 11. IE11 has a bunch of new under-the-covers features that will undoubtedly lead to a better browser. It includes WebGL support, which increases graphics rendering speeds substantially. Mozilla invented WebGL. IE11 also has SPDY support, which speeds up loading times. Google invented SPDY. There's also a gaggle of new developer tools. Metro IE11 and Desktop IE11 should be syncing tabs, but they aren't. It isn't clear if that's beta blues or if Microsoft has something else in mind.

Windows Store. The new Windows 8.1 version of Windows Store (Figure 9) doesn't look or act anything at all like the Windows 8 version. In some respects, that's a good thing. In other respects, it doesn't matter much -- the content in the Store hasn't changed. On that score, Facebook and Flipboard now promise that they will provide Metro apps, one of these days -- quite a revelation, considering Microsoft owns 1.6 percent of Facebook.

Figure 9: The Windows Store has fancy new digs, and big-name apps are on the way.

Microsoft showed off a number of additional Windows 8.1 goodies: native support for 3D printers; rudimentary photo editing tools, not in the same league as iPhoto, much less Instagram; a cookbook app that advances page by page by waving your hand, so you won't get the screen dirty; a build-it-yourself gaming app; fingerprint login; alarm clock; Metro calculator; Reading List (a reduced-functionality Evernote); a new camera app with Photosynth stitching, and several more. An app for Lego Mindstorms is in the wings, although the iOS and Android Mindstorms EV3 app has been around for six months.

The Microsoft-supplied Metro apps are in for big changes -- due to appear before Win8.1 ships -- with Bing now powering many of the offerings, including Food & Drink, Health & Fitness, and Help & Tips. The final version of Xbox Music, we're assured, will actually play music, instead of just trying to sell it. Video is supposed to be de-fanged as well.

I encountered many stability problems with Windows 8.1. Clicking or tapping on options in Microsoft's own Metro apps frequently dumped me back on the Metro Start screen. Trying to move around Metro snapped panes led to freezes and bizarre displays. I couldn't get live tiles to update. Icing on the cake, the 64-bit version is so slow on a Windows 8 Hyper-V VM that I frequently found myself twiddling my thumbs. It's definitely a beta.

The verdictIf anybody at Microsoft really believes that Windows 8.1 will turn the tide of public sentiment against Windows 8, they're sorely mistaken. If Microsoft had the willingness or wherewithal to implement something akin to the Windows Red proposal, both consumers and business users would have more cause to be excited about the next version of Windows. As it stands, Windows 8.1 will rightfully be viewed as another missed opportunity.

That said, if you have Windows 8, by either an error of omission or commission, you should definitely install Windows 8.1 when it's available. Win 8.1 embodies serious benefits on the Metro side, tiny improvements to the Desktop side, and no noticeable downsides to either.